The Holley model 2280 is a 2 barrel carburetor with a 1 1/4" SAE flange, which is the small 2 barrel flange shared with small base Rochester 2-Jets, Carter BBDs and Stromberg WWs. Bolt centers on this flange are 1.87 X 3.250".
The 2280 was used mostly on Chrysler 318 engines and the Slant 6 from 1977-1987. Model 6280 was a feedback version used on US-production cars and some trucks from 1985-1989.
Carburetor numbers are stamped on the side of the float bowl in this model. How to find Holley carburetor list numbers